/*
  * Apple HTTP Live Streaming demuxer
  * Copyright (c) 2010 Martin Storsjo

  * Copyright (c) 2013 Anssi Hannula

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * Apple HTTP Live Streaming demuxer
  * http://tools.ietf.org/html/draft-pantos-http-live-streaming
  */
 
 #include "libavutil/avstring.h"

 #include "libavutil/avassert.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/mathematics.h"

 #include "libavutil/opt.h"

 #include "libavutil/dict.h"

 #include "libavutil/time.h"

 #include "avformat.h"
 #include "internal.h"

 #include "avio_internal.h"

 #include "url.h"

 #include "id3v2.h"

 
 #define INITIAL_BUFFER_SIZE 32768

 #define MAX_FIELD_LEN 64
 #define MAX_CHARACTERISTICS_LEN 512
 

 #define MPEG_TIME_BASE 90000
 #define MPEG_TIME_BASE_Q (AVRational){1, MPEG_TIME_BASE}
 

 /*
  * An apple http stream consists of a playlist with media segment files,
  * played sequentially. There may be several playlists with the same
  * video content, in different bandwidth variants, that are played in

  * parallel (preferably only one bandwidth variant at a time). In this case,

  * the user supplied the url to a main playlist that only lists the variant
  * playlists.
  *
  * If the main playlist doesn't point at any variants, we still create
  * one anonymous toplevel variant for this, to maintain the structure.
  */
 

 enum KeyType {
     KEY_NONE,
     KEY_AES_128,

     KEY_SAMPLE_AES

 };
 

 struct segment {

     int64_t duration;

     int64_t url_offset;
     int64_t size;

     char *url;
     char *key;

     enum KeyType key_type;
     uint8_t iv[16];

 };
 

 struct rendition;
 

 enum PlaylistType {
     PLS_TYPE_UNSPECIFIED,
     PLS_TYPE_EVENT,
     PLS_TYPE_VOD
 };
 

 /*

  * Each playlist has its own demuxer. If it currently is active,

  * it has an open AVIOContext too, and potentially an AVPacket

  * containing the next packet from this stream.
  */

 struct playlist {

     char url[MAX_URL_SIZE];

     AVIOContext pb;
     uint8_t* read_buffer;
     URLContext *input;
     AVFormatContext *parent;
     int index;

     AVFormatContext *ctx;
     AVPacket pkt;
     int stream_offset;
 

     int finished;

     enum PlaylistType type;

     int64_t target_duration;

     int start_seq_no;
     int n_segments;
     struct segment **segments;

     int needed, cur_needed;
     int cur_seq_no;

     int64_t cur_seg_offset;

     int64_t last_load_time;

 
     char key_url[MAX_URL_SIZE];
     uint8_t key[16];

     /* ID3 timestamp handling (elementary audio streams have ID3 timestamps
      * (and possibly other ID3 tags) in the beginning of each segment) */
     int is_id3_timestamped; /* -1: not yet known */
     int64_t id3_mpegts_timestamp; /* in mpegts tb */
     int64_t id3_offset; /* in stream original tb */
     uint8_t* id3_buf; /* temp buffer for id3 parsing */
     unsigned int id3_buf_size;
     AVDictionary *id3_initial; /* data from first id3 tag */
     int id3_found; /* ID3 tag found at some point */
     int id3_changed; /* ID3 tag data has changed at some point */
     ID3v2ExtraMeta *id3_deferred_extra; /* stored here until subdemuxer is opened */
 

     int64_t seek_timestamp;
     int seek_flags;

     int seek_stream_index; /* into subdemuxer stream array */

     /* Renditions associated with this playlist, if any.
      * Alternative rendition playlists have a single rendition associated
      * with them, and variant main Media Playlists may have
      * multiple (playlist-less) renditions associated with them. */
     int n_renditions;
     struct rendition **renditions;
 };
 
 /*
  * Renditions are e.g. alternative subtitle or audio streams.
  * The rendition may either be an external playlist or it may be
  * contained in the main Media Playlist of the variant (in which case
  * playlist is NULL).
  */
 struct rendition {
     enum AVMediaType type;
     struct playlist *playlist;
     char group_id[MAX_FIELD_LEN];
     char language[MAX_FIELD_LEN];
     char name[MAX_FIELD_LEN];
     int disposition;

 };
 

 struct variant {
     int bandwidth;

 
     /* every variant contains at least the main Media Playlist in index 0 */

     int n_playlists;
     struct playlist **playlists;

 
     char audio_group[MAX_FIELD_LEN];
     char video_group[MAX_FIELD_LEN];
     char subtitles_group[MAX_FIELD_LEN];

 };
 

 typedef struct HLSContext {

     AVClass *class;

     int n_variants;
     struct variant **variants;

     int n_playlists;
     struct playlist **playlists;

     int n_renditions;
     struct rendition **renditions;

     int cur_seq_no;

     int live_start_index;

     int first_packet;

     int64_t first_timestamp;

     int64_t cur_timestamp;

     AVIOInterruptCB *interrupt_callback;

     char *user_agent;                    ///< holds HTTP user agent set as an AVOption to the HTTP protocol context
     char *cookies;                       ///< holds HTTP cookie values set in either the initial response or as an AVOption to the HTTP protocol context

     char *headers;                       ///< holds HTTP headers set as an AVOption to the HTTP protocol context

 } HLSContext;

 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)

 {
     int len = ff_get_line(s, buf, maxlen);

     while (len > 0 && av_isspace(buf[len - 1]))

         buf[--len] = '\0';
     return len;
 }
 

 static void free_segment_list(struct playlist *pls)

 {
     int i;

     for (i = 0; i < pls->n_segments; i++) {

         av_freep(&pls->segments[i]->key);
         av_freep(&pls->segments[i]->url);
         av_freep(&pls->segments[i]);

     }

     av_freep(&pls->segments);
     pls->n_segments = 0;
 }
 
 static void free_playlist_list(HLSContext *c)
 {
     int i;
     for (i = 0; i < c->n_playlists; i++) {
         struct playlist *pls = c->playlists[i];
         free_segment_list(pls);

         av_freep(&pls->renditions);

         av_freep(&pls->id3_buf);
         av_dict_free(&pls->id3_initial);
         ff_id3v2_free_extra_meta(&pls->id3_deferred_extra);

         av_free_packet(&pls->pkt);

         av_freep(&pls->pb.buffer);

         if (pls->input)
             ffurl_close(pls->input);
         if (pls->ctx) {
             pls->ctx->pb = NULL;
             avformat_close_input(&pls->ctx);
         }
         av_free(pls);
     }
     av_freep(&c->playlists);
     av_freep(&c->cookies);
     av_freep(&c->user_agent);
     c->n_playlists = 0;

 }
 

 static void free_variant_list(HLSContext *c)

 {
     int i;
     for (i = 0; i < c->n_variants; i++) {
         struct variant *var = c->variants[i];

         av_freep(&var->playlists);

         av_free(var);
     }
     av_freep(&c->variants);
     c->n_variants = 0;
 }
 

 static void free_rendition_list(HLSContext *c)
 {
     int i;
     for (i = 0; i < c->n_renditions; i++)

         av_freep(&c->renditions[i]);

     av_freep(&c->renditions);
     c->n_renditions = 0;
 }
 

 /*
  * Used to reset a statically allocated AVPacket to a clean slate,
  * containing no data.
  */
 static void reset_packet(AVPacket *pkt)
 {
     av_init_packet(pkt);
     pkt->data = NULL;
 }
 

 static struct playlist *new_playlist(HLSContext *c, const char *url,
                                      const char *base)
 {
     struct playlist *pls = av_mallocz(sizeof(struct playlist));
     if (!pls)
         return NULL;
     reset_packet(&pls->pkt);
     ff_make_absolute_url(pls->url, sizeof(pls->url), base, url);

     pls->seek_timestamp = AV_NOPTS_VALUE;

 
     pls->is_id3_timestamped = -1;
     pls->id3_mpegts_timestamp = AV_NOPTS_VALUE;
 

     dynarray_add(&c->playlists, &c->n_playlists, pls);
     return pls;
 }
 

 struct variant_info {
     char bandwidth[20];
     /* variant group ids: */
     char audio[MAX_FIELD_LEN];
     char video[MAX_FIELD_LEN];
     char subtitles[MAX_FIELD_LEN];
 };
 
 static struct variant *new_variant(HLSContext *c, struct variant_info *info,

                                    const char *url, const char *base)
 {

     struct variant *var;
     struct playlist *pls;
 
     pls = new_playlist(c, url, base);
     if (!pls)
         return NULL;
 
     var = av_mallocz(sizeof(struct variant));

     if (!var)
         return NULL;

     if (info) {
         var->bandwidth = atoi(info->bandwidth);
         strcpy(var->audio_group, info->audio);
         strcpy(var->video_group, info->video);
         strcpy(var->subtitles_group, info->subtitles);
     }
 

     dynarray_add(&c->variants, &c->n_variants, var);

     dynarray_add(&var->playlists, &var->n_playlists, pls);

     return var;
 }
 
 static void handle_variant_args(struct variant_info *info, const char *key,
                                 int key_len, char **dest, int *dest_len)
 {

     if (!strncmp(key, "BANDWIDTH=", key_len)) {

         *dest     =        info->bandwidth;
         *dest_len = sizeof(info->bandwidth);

     } else if (!strncmp(key, "AUDIO=", key_len)) {
         *dest     =        info->audio;
         *dest_len = sizeof(info->audio);
     } else if (!strncmp(key, "VIDEO=", key_len)) {
         *dest     =        info->video;
         *dest_len = sizeof(info->video);
     } else if (!strncmp(key, "SUBTITLES=", key_len)) {
         *dest     =        info->subtitles;
         *dest_len = sizeof(info->subtitles);

     }
 }
 

 struct key_info {
      char uri[MAX_URL_SIZE];

      char method[11];

      char iv[35];
 };
 
 static void handle_key_args(struct key_info *info, const char *key,
                             int key_len, char **dest, int *dest_len)
 {
     if (!strncmp(key, "METHOD=", key_len)) {
         *dest     =        info->method;
         *dest_len = sizeof(info->method);
     } else if (!strncmp(key, "URI=", key_len)) {
         *dest     =        info->uri;
         *dest_len = sizeof(info->uri);
     } else if (!strncmp(key, "IV=", key_len)) {
         *dest     =        info->iv;
         *dest_len = sizeof(info->iv);
     }
 }
 

 struct rendition_info {
     char type[16];
     char uri[MAX_URL_SIZE];
     char group_id[MAX_FIELD_LEN];
     char language[MAX_FIELD_LEN];
     char assoc_language[MAX_FIELD_LEN];
     char name[MAX_FIELD_LEN];
     char defaultr[4];
     char forced[4];
     char characteristics[MAX_CHARACTERISTICS_LEN];
 };
 
 static struct rendition *new_rendition(HLSContext *c, struct rendition_info *info,
                                       const char *url_base)
 {
     struct rendition *rend;
     enum AVMediaType type = AVMEDIA_TYPE_UNKNOWN;
     char *characteristic;
     char *chr_ptr;
     char *saveptr;
 
     if (!strcmp(info->type, "AUDIO"))
         type = AVMEDIA_TYPE_AUDIO;
     else if (!strcmp(info->type, "VIDEO"))
         type = AVMEDIA_TYPE_VIDEO;
     else if (!strcmp(info->type, "SUBTITLES"))
         type = AVMEDIA_TYPE_SUBTITLE;
     else if (!strcmp(info->type, "CLOSED-CAPTIONS"))
         /* CLOSED-CAPTIONS is ignored since we do not support CEA-608 CC in
          * AVC SEI RBSP anyway */
         return NULL;
 
     if (type == AVMEDIA_TYPE_UNKNOWN)
         return NULL;
 
     /* URI is mandatory for subtitles as per spec */
     if (type == AVMEDIA_TYPE_SUBTITLE && !info->uri[0])
         return NULL;
 
     /* TODO: handle subtitles (each segment has to parsed separately) */
     if (type == AVMEDIA_TYPE_SUBTITLE)
         return NULL;
 
     rend = av_mallocz(sizeof(struct rendition));
     if (!rend)
         return NULL;
 
     dynarray_add(&c->renditions, &c->n_renditions, rend);
 
     rend->type = type;
     strcpy(rend->group_id, info->group_id);
     strcpy(rend->language, info->language);
     strcpy(rend->name, info->name);
 
     /* add the playlist if this is an external rendition */
     if (info->uri[0]) {
         rend->playlist = new_playlist(c, info->uri, url_base);
         if (rend->playlist)
             dynarray_add(&rend->playlist->renditions,
                          &rend->playlist->n_renditions, rend);
     }
 
     if (info->assoc_language[0]) {
         int langlen = strlen(rend->language);
         if (langlen < sizeof(rend->language) - 3) {
             rend->language[langlen] = ',';
             strncpy(rend->language + langlen + 1, info->assoc_language,
                     sizeof(rend->language) - langlen - 2);
         }
     }
 
     if (!strcmp(info->defaultr, "YES"))
         rend->disposition |= AV_DISPOSITION_DEFAULT;
     if (!strcmp(info->forced, "YES"))
         rend->disposition |= AV_DISPOSITION_FORCED;
 
     chr_ptr = info->characteristics;
     while ((characteristic = av_strtok(chr_ptr, ",", &saveptr))) {
         if (!strcmp(characteristic, "public.accessibility.describes-music-and-sound"))
             rend->disposition |= AV_DISPOSITION_HEARING_IMPAIRED;
         else if (!strcmp(characteristic, "public.accessibility.describes-video"))
             rend->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED;
 
         chr_ptr = NULL;
     }
 
     return rend;
 }
 
 static void handle_rendition_args(struct rendition_info *info, const char *key,
                                   int key_len, char **dest, int *dest_len)
 {
     if (!strncmp(key, "TYPE=", key_len)) {
         *dest     =        info->type;
         *dest_len = sizeof(info->type);
     } else if (!strncmp(key, "URI=", key_len)) {
         *dest     =        info->uri;
         *dest_len = sizeof(info->uri);
     } else if (!strncmp(key, "GROUP-ID=", key_len)) {
         *dest     =        info->group_id;
         *dest_len = sizeof(info->group_id);
     } else if (!strncmp(key, "LANGUAGE=", key_len)) {
         *dest     =        info->language;
         *dest_len = sizeof(info->language);
     } else if (!strncmp(key, "ASSOC-LANGUAGE=", key_len)) {
         *dest     =        info->assoc_language;
         *dest_len = sizeof(info->assoc_language);
     } else if (!strncmp(key, "NAME=", key_len)) {
         *dest     =        info->name;
         *dest_len = sizeof(info->name);
     } else if (!strncmp(key, "DEFAULT=", key_len)) {
         *dest     =        info->defaultr;
         *dest_len = sizeof(info->defaultr);
     } else if (!strncmp(key, "FORCED=", key_len)) {
         *dest     =        info->forced;
         *dest_len = sizeof(info->forced);
     } else if (!strncmp(key, "CHARACTERISTICS=", key_len)) {
         *dest     =        info->characteristics;
         *dest_len = sizeof(info->characteristics);
     }
     /*
      * ignored:
      * - AUTOSELECT: client may autoselect based on e.g. system language
      * - INSTREAM-ID: EIA-608 closed caption number ("CC1".."CC4")
      */
 }
 

 /* used by parse_playlist to allocate a new variant+playlist when the
  * playlist is detected to be a Media Playlist (not Master Playlist)
  * and we have no parent Master Playlist (parsing of which would have
  * allocated the variant and playlist already) */
 static int ensure_playlist(HLSContext *c, struct playlist **pls, const char *url)
 {
     if (*pls)
         return 0;
     if (!new_variant(c, NULL, url, NULL))
         return AVERROR(ENOMEM);
     *pls = c->playlists[c->n_playlists - 1];
     return 0;
 }
 
 /* pls = NULL  => Master Playlist or parentless Media Playlist
  * pls = !NULL => parented Media Playlist, playlist+variant allocated */

 static int parse_playlist(HLSContext *c, const char *url,

                           struct playlist *pls, AVIOContext *in)

 {

     int ret = 0, is_segment = 0, is_variant = 0;

     int64_t duration = 0;

     enum KeyType key_type = KEY_NONE;
     uint8_t iv[16] = "";
     int has_iv = 0;

     char key[MAX_URL_SIZE] = "";

     char line[MAX_URL_SIZE];

     const char *ptr;
     int close_in = 0;

     int64_t seg_offset = 0;
     int64_t seg_size = -1;

     uint8_t *new_url = NULL;

     struct variant_info variant_info;

     char tmp_str[MAX_URL_SIZE];

 
     if (!in) {

         AVDictionary *opts = NULL;

         close_in = 1;

         /* Some HLS servers don't like being sent the range header */

         av_dict_set(&opts, "seekable", "0", 0);

 
         // broker prior HTTP options that should be consistent across requests
         av_dict_set(&opts, "user-agent", c->user_agent, 0);
         av_dict_set(&opts, "cookies", c->cookies, 0);

         av_dict_set(&opts, "headers", c->headers, 0);

         ret = avio_open2(&in, url, AVIO_FLAG_READ,
                          c->interrupt_callback, &opts);
         av_dict_free(&opts);
         if (ret < 0)

             return ret;
     }
 

     if (av_opt_get(in, "location", AV_OPT_SEARCH_CHILDREN, &new_url) >= 0)
         url = new_url;
 

     read_chomp_line(in, line, sizeof(line));
     if (strcmp(line, "#EXTM3U")) {
         ret = AVERROR_INVALIDDATA;
         goto fail;
     }
 

     if (pls) {
         free_segment_list(pls);
         pls->finished = 0;

         pls->type = PLS_TYPE_UNSPECIFIED;

     }

     while (!avio_feof(in)) {

         read_chomp_line(in, line, sizeof(line));
         if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
             is_variant = 1;

             memset(&variant_info, 0, sizeof(variant_info));

             ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,

                                &variant_info);

         } else if (av_strstart(line, "#EXT-X-KEY:", &ptr)) {
             struct key_info info = {{0}};
             ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_key_args,
                                &info);
             key_type = KEY_NONE;
             has_iv = 0;
             if (!strcmp(info.method, "AES-128"))
                 key_type = KEY_AES_128;

             if (!strcmp(info.method, "SAMPLE-AES"))
                 key_type = KEY_SAMPLE_AES;

             if (!strncmp(info.iv, "0x", 2) || !strncmp(info.iv, "0X", 2)) {
                 ff_hex_to_data(iv, info.iv + 2);
                 has_iv = 1;
             }
             av_strlcpy(key, info.uri, sizeof(key));

         } else if (av_strstart(line, "#EXT-X-MEDIA:", &ptr)) {
             struct rendition_info info = {{0}};
             ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_rendition_args,
                                &info);
             new_rendition(c, &info, url);

         } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {

             ret = ensure_playlist(c, &pls, url);
             if (ret < 0)
                 goto fail;

             pls->target_duration = atoi(ptr) * AV_TIME_BASE;

         } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {

             ret = ensure_playlist(c, &pls, url);
             if (ret < 0)
                 goto fail;

             pls->start_seq_no = atoi(ptr);

         } else if (av_strstart(line, "#EXT-X-PLAYLIST-TYPE:", &ptr)) {
             ret = ensure_playlist(c, &pls, url);
             if (ret < 0)
                 goto fail;
             if (!strcmp(ptr, "EVENT"))
                 pls->type = PLS_TYPE_EVENT;
             else if (!strcmp(ptr, "VOD"))
                 pls->type = PLS_TYPE_VOD;

         } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {

             if (pls)
                 pls->finished = 1;

         } else if (av_strstart(line, "#EXTINF:", &ptr)) {
             is_segment = 1;

             duration   = atof(ptr) * AV_TIME_BASE;

         } else if (av_strstart(line, "#EXT-X-BYTERANGE:", &ptr)) {
             seg_size = atoi(ptr);
             ptr = strchr(ptr, '@');
             if (ptr)
                 seg_offset = atoi(ptr+1);

         } else if (av_strstart(line, "#", NULL)) {
             continue;
         } else if (line[0]) {
             if (is_variant) {

                 if (!new_variant(c, &variant_info, line, url)) {

                     ret = AVERROR(ENOMEM);
                     goto fail;
                 }
                 is_variant = 0;
             }
             if (is_segment) {
                 struct segment *seg;

                 if (!pls) {
                     if (!new_variant(c, 0, url, NULL)) {

                         ret = AVERROR(ENOMEM);
                         goto fail;
                     }

                     pls = c->playlists[c->n_playlists - 1];

                 }
                 seg = av_malloc(sizeof(struct segment));
                 if (!seg) {
                     ret = AVERROR(ENOMEM);
                     goto fail;
                 }
                 seg->duration = duration;

                 seg->key_type = key_type;
                 if (has_iv) {
                     memcpy(seg->iv, iv, sizeof(iv));
                 } else {

                     int seq = pls->start_seq_no + pls->n_segments;

                     memset(seg->iv, 0, sizeof(seg->iv));
                     AV_WB32(seg->iv + 12, seq);
                 }

 
                 if (key_type != KEY_NONE) {
                     ff_make_absolute_url(tmp_str, sizeof(tmp_str), url, key);
                     seg->key = av_strdup(tmp_str);
                     if (!seg->key) {
                         av_free(seg);
                         ret = AVERROR(ENOMEM);
                         goto fail;
                     }
                 } else {
                     seg->key = NULL;
                 }
 
                 ff_make_absolute_url(tmp_str, sizeof(tmp_str), url, line);
                 seg->url = av_strdup(tmp_str);
                 if (!seg->url) {
                     av_free(seg->key);
                     av_free(seg);
                     ret = AVERROR(ENOMEM);
                     goto fail;
                 }
 

                 dynarray_add(&pls->segments, &pls->n_segments, seg);

                 is_segment = 0;

 
                 seg->size = seg_size;
                 if (seg_size >= 0) {
                     seg->url_offset = seg_offset;
                     seg_offset += seg_size;
                     seg_size = -1;
                 } else {
                     seg->url_offset = 0;
                     seg_offset = 0;
                 }

             }
         }
     }

     if (pls)

         pls->last_load_time = av_gettime_relative();

 
 fail:

     av_free(new_url);

     if (close_in)

         avio_close(in);

     return ret;
 }
 

 enum ReadFromURLMode {
     READ_NORMAL,
     READ_COMPLETE,
 };
 

 /* read from URLContext, limiting read to current segment */

 static int read_from_url(struct playlist *pls, uint8_t *buf, int buf_size,
                          enum ReadFromURLMode mode)

 {
     int ret;
     struct segment *seg = pls->segments[pls->cur_seq_no - pls->start_seq_no];
 
      /* limit read if the segment was only a part of a file */
     if (seg->size >= 0)
         buf_size = FFMIN(buf_size, seg->size - pls->cur_seg_offset);
 

     if (mode == READ_COMPLETE)
         ret = ffurl_read_complete(pls->input, buf, buf_size);
     else
         ret = ffurl_read(pls->input, buf, buf_size);

 
     if (ret > 0)
         pls->cur_seg_offset += ret;
 
     return ret;
 }
 

 /* Parse the raw ID3 data and pass contents to caller */
 static void parse_id3(AVFormatContext *s, AVIOContext *pb,
                       AVDictionary **metadata, int64_t *dts,
                       ID3v2ExtraMetaAPIC **apic, ID3v2ExtraMeta **extra_meta)
 {
     static const char id3_priv_owner_ts[] = "com.apple.streaming.transportStreamTimestamp";
     ID3v2ExtraMeta *meta;
 
     ff_id3v2_read_dict(pb, metadata, ID3v2_DEFAULT_MAGIC, extra_meta);
     for (meta = *extra_meta; meta; meta = meta->next) {
         if (!strcmp(meta->tag, "PRIV")) {
             ID3v2ExtraMetaPRIV *priv = meta->data;
             if (priv->datasize == 8 && !strcmp(priv->owner, id3_priv_owner_ts)) {
                 /* 33-bit MPEG timestamp */
                 int64_t ts = AV_RB64(priv->data);
                 av_log(s, AV_LOG_DEBUG, "HLS ID3 audio timestamp %"PRId64"\n", ts);
                 if ((ts & ~((1ULL << 33) - 1)) == 0)
                     *dts = ts;
                 else
                     av_log(s, AV_LOG_ERROR, "Invalid HLS ID3 audio timestamp %"PRId64"\n", ts);
             }
         } else if (!strcmp(meta->tag, "APIC") && apic)
             *apic = meta->data;
     }
 }
 
 /* Check if the ID3 metadata contents have changed */
 static int id3_has_changed_values(struct playlist *pls, AVDictionary *metadata,
                                   ID3v2ExtraMetaAPIC *apic)
 {
     AVDictionaryEntry *entry = NULL;
     AVDictionaryEntry *oldentry;
     /* check that no keys have changed values */
     while ((entry = av_dict_get(metadata, "", entry, AV_DICT_IGNORE_SUFFIX))) {
         oldentry = av_dict_get(pls->id3_initial, entry->key, NULL, AV_DICT_MATCH_CASE);
         if (!oldentry || strcmp(oldentry->value, entry->value) != 0)
             return 1;
     }
 
     /* check if apic appeared */
     if (apic && (pls->ctx->nb_streams != 2 || !pls->ctx->streams[1]->attached_pic.data))
         return 1;
 
     if (apic) {
         int size = pls->ctx->streams[1]->attached_pic.size;
         if (size != apic->buf->size - FF_INPUT_BUFFER_PADDING_SIZE)
             return 1;
 
         if (memcmp(apic->buf->data, pls->ctx->streams[1]->attached_pic.data, size) != 0)
             return 1;
     }
 
     return 0;
 }
 
 /* Parse ID3 data and handle the found data */
 static void handle_id3(AVIOContext *pb, struct playlist *pls)
 {
     AVDictionary *metadata = NULL;
     ID3v2ExtraMetaAPIC *apic = NULL;
     ID3v2ExtraMeta *extra_meta = NULL;
     int64_t timestamp = AV_NOPTS_VALUE;
 
     parse_id3(pls->ctx, pb, &metadata, &timestamp, &apic, &extra_meta);
 
     if (timestamp != AV_NOPTS_VALUE) {
         pls->id3_mpegts_timestamp = timestamp;
         pls->id3_offset = 0;
     }
 
     if (!pls->id3_found) {
         /* initial ID3 tags */
         av_assert0(!pls->id3_deferred_extra);
         pls->id3_found = 1;
 
         /* get picture attachment and set text metadata */
         if (pls->ctx->nb_streams)
             ff_id3v2_parse_apic(pls->ctx, &extra_meta);
         else
             /* demuxer not yet opened, defer picture attachment */
             pls->id3_deferred_extra = extra_meta;
 
         av_dict_copy(&pls->ctx->metadata, metadata, 0);
         pls->id3_initial = metadata;
 
     } else {
         if (!pls->id3_changed && id3_has_changed_values(pls, metadata, apic)) {
             avpriv_report_missing_feature(pls->ctx, "Changing ID3 metadata in HLS audio elementary stream");
             pls->id3_changed = 1;
         }
         av_dict_free(&metadata);
     }
 
     if (!pls->id3_deferred_extra)
         ff_id3v2_free_extra_meta(&extra_meta);
 }
 
 /* Intercept and handle ID3 tags between URLContext and AVIOContext */
 static void intercept_id3(struct playlist *pls, uint8_t *buf,
                          int buf_size, int *len)
 {
     /* intercept id3 tags, we do not want to pass them to the raw
      * demuxer on all segment switches */
     int bytes;
     int id3_buf_pos = 0;
     int fill_buf = 0;
 
     /* gather all the id3 tags */
     while (1) {
         /* see if we can retrieve enough data for ID3 header */
         if (*len < ID3v2_HEADER_SIZE && buf_size >= ID3v2_HEADER_SIZE) {
             bytes = read_from_url(pls, buf + *len, ID3v2_HEADER_SIZE - *len, READ_COMPLETE);
             if (bytes > 0) {
 
                 if (bytes == ID3v2_HEADER_SIZE - *len)
                     /* no EOF yet, so fill the caller buffer again after
                      * we have stripped the ID3 tags */
                     fill_buf = 1;
 
                 *len += bytes;
 
             } else if (*len <= 0) {
                 /* error/EOF */
                 *len = bytes;
                 fill_buf = 0;
             }
         }
 
         if (*len < ID3v2_HEADER_SIZE)
             break;
 
         if (ff_id3v2_match(buf, ID3v2_DEFAULT_MAGIC)) {
             struct segment *seg = pls->segments[pls->cur_seq_no - pls->start_seq_no];

             int64_t maxsize = seg->size >= 0 ? seg->size : 1024*1024;

             int taglen = ff_id3v2_tag_len(buf);
             int tag_got_bytes = FFMIN(taglen, *len);
             int remaining = taglen - tag_got_bytes;
 

             if (taglen > maxsize) {
                 av_log(pls->ctx, AV_LOG_ERROR, "Too large HLS ID3 tag (%d > %"PRId64" bytes)\n",
                        taglen, maxsize);

                 break;
             }
 
             /*
              * Copy the id3 tag to our temporary id3 buffer.
              * We could read a small id3 tag directly without memcpy, but
              * we would still need to copy the large tags, and handling
              * both of those cases together with the possibility for multiple
              * tags would make the handling a bit complex.
              */
             pls->id3_buf = av_fast_realloc(pls->id3_buf, &pls->id3_buf_size, id3_buf_pos + taglen);
             if (!pls->id3_buf)
                 break;
             memcpy(pls->id3_buf + id3_buf_pos, buf, tag_got_bytes);
             id3_buf_pos += tag_got_bytes;
 
             /* strip the intercepted bytes */
             *len -= tag_got_bytes;
             memmove(buf, buf + tag_got_bytes, *len);
             av_log(pls->ctx, AV_LOG_DEBUG, "Stripped %d HLS ID3 bytes\n", tag_got_bytes);
 
             if (remaining > 0) {
                 /* read the rest of the tag in */
                 if (read_from_url(pls, pls->id3_buf + id3_buf_pos, remaining, READ_COMPLETE) != remaining)
                     break;
                 id3_buf_pos += remaining;
                 av_log(pls->ctx, AV_LOG_DEBUG, "Stripped additional %d HLS ID3 bytes\n", remaining);
             }
 
         } else {
             /* no more ID3 tags */
             break;
         }
     }
 
     /* re-fill buffer for the caller unless EOF */
     if (*len >= 0 && (fill_buf || *len == 0)) {
         bytes = read_from_url(pls, buf + *len, buf_size - *len, READ_NORMAL);
 
         /* ignore error if we already had some data */
         if (bytes >= 0)
             *len += bytes;
         else if (*len == 0)
             *len = bytes;
     }
 
     if (pls->id3_buf) {
         /* Now parse all the ID3 tags */
         AVIOContext id3ioctx;
         ffio_init_context(&id3ioctx, pls->id3_buf, id3_buf_pos, 0, NULL, NULL, NULL, NULL);
         handle_id3(&id3ioctx, pls);
     }
 
     if (pls->is_id3_timestamped == -1)
         pls->is_id3_timestamped = (pls->id3_mpegts_timestamp != AV_NOPTS_VALUE);
 }
 

 static void update_options(char **dest, const char *name, void *src)
 {
     av_freep(dest);
     av_opt_get(src, name, 0, (uint8_t**)dest);
     if (*dest && !strlen(*dest))
         av_freep(dest);
 }
 

 static int open_input(HLSContext *c, struct playlist *pls)

 {

     AVDictionary *opts = NULL;

     AVDictionary *opts2 = NULL;

     int ret;

     struct segment *seg = pls->segments[pls->cur_seq_no - pls->start_seq_no];

 
     // broker prior HTTP options that should be consistent across requests
     av_dict_set(&opts, "user-agent", c->user_agent, 0);
     av_dict_set(&opts, "cookies", c->cookies, 0);

     av_dict_set(&opts, "headers", c->headers, 0);

     av_dict_set(&opts, "seekable", "0", 0);

     // Same opts for key request (ffurl_open mutilates the opts so it cannot be used twice)
     av_dict_copy(&opts2, opts, 0);
 

     if (seg->size >= 0) {
         /* try to restrict the HTTP request to the part we want
          * (if this is in fact a HTTP request) */

         av_dict_set_int(&opts, "offset", seg->url_offset, 0);
         av_dict_set_int(&opts, "end_offset", seg->url_offset + seg->size, 0);

     }
 

     av_log(pls->parent, AV_LOG_VERBOSE, "HLS request for url '%s', offset %"PRId64", playlist %d\n",
            seg->url, seg->url_offset, pls->index);
 

     if (seg->key_type == KEY_NONE) {

         ret = ffurl_open(&pls->input, seg->url, AVIO_FLAG_READ,
                           &pls->parent->interrupt_callback, &opts);

     } else if (seg->key_type == KEY_AES_128) {
         char iv[33], key[33], url[MAX_URL_SIZE];

         if (strcmp(seg->key, pls->key_url)) {

             URLContext *uc;

             if (ffurl_open(&uc, seg->key, AVIO_FLAG_READ,

                            &pls->parent->interrupt_callback, &opts2) == 0) {

                 if (ffurl_read_complete(uc, pls->key, sizeof(pls->key))
                     != sizeof(pls->key)) {

                     av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n",
                            seg->key);
                 }

                 update_options(&c->cookies, "cookies", uc->priv_data);

                 av_dict_set(&opts, "cookies", c->cookies, 0);

                 ffurl_close(uc);
             } else {
                 av_log(NULL, AV_LOG_ERROR, "Unable to open key file %s\n",
                        seg->key);
             }

             av_strlcpy(pls->key_url, seg->key, sizeof(pls->key_url));

         }
         ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0);

         ff_data_to_hex(key, pls->key, sizeof(pls->key), 0);

         iv[32] = key[32] = '\0';
         if (strstr(seg->url, "://"))
             snprintf(url, sizeof(url), "crypto+%s", seg->url);
         else
             snprintf(url, sizeof(url), "crypto:%s", seg->url);

         if ((ret = ffurl_alloc(&pls->input, url, AVIO_FLAG_READ,
                                &pls->parent->interrupt_callback)) < 0)

             goto cleanup;

         av_opt_set(pls->input->priv_data, "key", key, 0);
         av_opt_set(pls->input->priv_data, "iv", iv, 0);

         if ((ret = ffurl_connect(pls->input, &opts)) < 0) {
             ffurl_close(pls->input);
             pls->input = NULL;

             goto cleanup;

         }

         ret = 0;

     } else if (seg->key_type == KEY_SAMPLE_AES) {
         av_log(pls->parent, AV_LOG_ERROR,
                "SAMPLE-AES encryption is not supported yet\n");
         ret = AVERROR_PATCHWELCOME;

     }

     else
       ret = AVERROR(ENOSYS);
 

     /* Seek to the requested position. If this was a HTTP request, the offset
      * should already be where want it to, but this allows e.g. local testing
      * without a HTTP server. */

     if (ret == 0 && seg->key_type == KEY_NONE) {

         int seekret = ffurl_seek(pls->input, seg->url_offset, SEEK_SET);
         if (seekret < 0) {
             av_log(pls->parent, AV_LOG_ERROR, "Unable to seek to offset %"PRId64" of HLS segment '%s'\n", seg->url_offset, seg->url);
             ret = seekret;
             ffurl_close(pls->input);
             pls->input = NULL;
         }
     }
 

 cleanup:
     av_dict_free(&opts);

     av_dict_free(&opts2);

     pls->cur_seg_offset = 0;

     return ret;

 }
 

 static int64_t default_reload_interval(struct playlist *pls)
 {
     return pls->n_segments > 0 ?
                           pls->segments[pls->n_segments - 1]->duration :
                           pls->target_duration;
 }
 

 static int read_data(void *opaque, uint8_t *buf, int buf_size)
 {

     struct playlist *v = opaque;

     HLSContext *c = v->parent->priv_data;

     int ret, i;

     int just_opened = 0;

 restart:

     if (!v->needed)
         return AVERROR_EOF;
 

     if (!v->input) {

         int64_t reload_interval;
 
         /* Check that the playlist is still needed before opening a new
          * segment. */
         if (v->ctx && v->ctx->nb_streams &&
             v->parent->nb_streams >= v->stream_offset + v->ctx->nb_streams) {
             v->needed = 0;
             for (i = v->stream_offset; i < v->stream_offset + v->ctx->nb_streams;
                 i++) {
                 if (v->parent->streams[i]->discard < AVDISCARD_ALL)
                     v->needed = 1;
             }
         }
         if (!v->needed) {
             av_log(v->parent, AV_LOG_INFO, "No longer receiving playlist %d\n",
                 v->index);
             return AVERROR_EOF;
         }
 

         /* If this is a live stream and the reload interval has elapsed since

          * the last playlist reload, reload the playlists now. */

         reload_interval = default_reload_interval(v);

 reload:

         if (!v->finished &&

             av_gettime_relative() - v->last_load_time >= reload_interval) {

             if ((ret = parse_playlist(c, v->url, v, NULL)) < 0) {
                 av_log(v->parent, AV_LOG_WARNING, "Failed to reload playlist %d\n",
                        v->index);

                 return ret;

             }

             /* If we need to reload the playlist again below (if
              * there's still no more segments), switch to a reload
              * interval of half the target duration. */

             reload_interval = v->target_duration / 2;

         }

         if (v->cur_seq_no < v->start_seq_no) {
             av_log(NULL, AV_LOG_WARNING,
                    "skipping %d segments ahead, expired from playlists\n",
                    v->start_seq_no - v->cur_seq_no);
             v->cur_seq_no = v->start_seq_no;
         }
         if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
             if (v->finished)
                 return AVERROR_EOF;

             while (av_gettime_relative() - v->last_load_time < reload_interval) {

                 if (ff_check_interrupt(c->interrupt_callback))

                     return AVERROR_EXIT;

                 av_usleep(100*1000);

             }
             /* Enough time has elapsed since the last reload */
             goto reload;
         }
 

         ret = open_input(c, v);

         if (ret < 0) {
             av_log(v->parent, AV_LOG_WARNING, "Failed to open segment of playlist %d\n",
                    v->index);

             v->cur_seq_no += 1;
             goto reload;

         }

         just_opened = 1;

     }

     ret = read_from_url(v, buf, buf_size, READ_NORMAL);

     if (ret > 0) {

         if (just_opened && v->is_id3_timestamped != 0) {
             /* Intercept ID3 tags here, elementary audio streams are required
              * to convey timestamps using them in the beginning of each segment. */
             intercept_id3(v, buf, buf_size, &ret);
         }
 

         return ret;

     }

     ffurl_close(v->input);

     v->input = NULL;
     v->cur_seq_no++;
 
     c->cur_seq_no = v->cur_seq_no;
 
     goto restart;
 }
 

 static int playlist_in_multiple_variants(HLSContext *c, struct playlist *pls)
 {
     int variant_count = 0;
     int i, j;
 
     for (i = 0; i < c->n_variants && variant_count < 2; i++) {
         struct variant *v = c->variants[i];
 
         for (j = 0; j < v->n_playlists; j++) {
             if (v->playlists[j] == pls) {
                 variant_count++;
                 break;
             }
         }
     }
 
     return variant_count >= 2;
 }
 

 static void add_renditions_to_variant(HLSContext *c, struct variant *var,
                                       enum AVMediaType type, const char *group_id)
 {
     int i;
 
     for (i = 0; i < c->n_renditions; i++) {
         struct rendition *rend = c->renditions[i];
 
         if (rend->type == type && !strcmp(rend->group_id, group_id)) {
 
             if (rend->playlist)
                 /* rendition is an external playlist
                  * => add the playlist to the variant */
                 dynarray_add(&var->playlists, &var->n_playlists, rend->playlist);
             else
                 /* rendition is part of the variant main Media Playlist
                  * => add the rendition to the main Media Playlist */
                 dynarray_add(&var->playlists[0]->renditions,
                              &var->playlists[0]->n_renditions,
                              rend);
         }
     }
 }
 
 static void add_metadata_from_renditions(AVFormatContext *s, struct playlist *pls,
                                          enum AVMediaType type)
 {
     int rend_idx = 0;
     int i;
 
     for (i = 0; i < pls->ctx->nb_streams; i++) {
         AVStream *st = s->streams[pls->stream_offset + i];
 
         if (st->codec->codec_type != type)
             continue;
 
         for (; rend_idx < pls->n_renditions; rend_idx++) {
             struct rendition *rend = pls->renditions[rend_idx];
 
             if (rend->type != type)
                 continue;
 
             if (rend->language[0])
                 av_dict_set(&st->metadata, "language", rend->language, 0);
             if (rend->name[0])
                 av_dict_set(&st->metadata, "comment", rend->name, 0);
 
             st->disposition |= rend->disposition;
         }
         if (rend_idx >=pls->n_renditions)
             break;
     }
 }
 

 /* if timestamp was in valid range: returns 1 and sets seq_no
  * if not: returns 0 and sets seq_no to closest segment */
 static int find_timestamp_in_playlist(HLSContext *c, struct playlist *pls,
                                       int64_t timestamp, int *seq_no)
 {
     int i;
     int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ?
                   0 : c->first_timestamp;
 
     if (timestamp < pos) {
         *seq_no = pls->start_seq_no;
         return 0;
     }
 
     for (i = 0; i < pls->n_segments; i++) {
         int64_t diff = pos + pls->segments[i]->duration - timestamp;
         if (diff > 0) {
             *seq_no = pls->start_seq_no + i;
             return 1;
         }
         pos += pls->segments[i]->duration;
     }
 
     *seq_no = pls->start_seq_no + pls->n_segments - 1;
 
     return 0;
 }
 

 static int select_cur_seq_no(HLSContext *c, struct playlist *pls)
 {
     int seq_no;
 
     if (!pls->finished && !c->first_packet &&

         av_gettime_relative() - pls->last_load_time >= default_reload_interval(pls))

         /* reload the playlist since it was suspended */
         parse_playlist(c, pls->url, pls, NULL);
 
     /* If playback is already in progress (we are just selecting a new
      * playlist) and this is a complete file, find the matching segment
      * by counting durations. */
     if (pls->finished && c->cur_timestamp != AV_NOPTS_VALUE) {
         find_timestamp_in_playlist(c, pls, c->cur_timestamp, &seq_no);
         return seq_no;
     }
 
     if (!pls->finished) {
         if (!c->first_packet && /* we are doing a segment selection during playback */
             c->cur_seq_no >= pls->start_seq_no &&
             c->cur_seq_no < pls->start_seq_no + pls->n_segments)
             /* While spec 3.4.3 says that we cannot assume anything about the
              * content at the same sequence number on different playlists,
              * in practice this seems to work and doing it otherwise would
              * require us to download a segment to inspect its timestamps. */
             return c->cur_seq_no;
 

         /* If this is a live stream, start live_start_index segments from the
          * start or end */
         if (c->live_start_index < 0)
             return pls->start_seq_no + FFMAX(pls->n_segments + c->live_start_index, 0);
         else
             return pls->start_seq_no + FFMIN(c->live_start_index, pls->n_segments - 1);

     }
 
     /* Otherwise just start on the first segment. */
     return pls->start_seq_no;
 }
 

 static int hls_read_header(AVFormatContext *s)

 {

     URLContext *u = (s->flags & AVFMT_FLAG_CUSTOM_IO) ? NULL : s->pb->opaque;

     HLSContext *c = s->priv_data;

     int ret = 0, i, j, stream_offset = 0;
 

     c->interrupt_callback = &s->interrupt_callback;
 

     c->first_packet = 1;
     c->first_timestamp = AV_NOPTS_VALUE;
     c->cur_timestamp = AV_NOPTS_VALUE;
 

     // if the URL context is good, read important options we must broker later

     if (u && u->prot->priv_data_class) {

         // get the previous user agent & set back to null if string size is zero

         update_options(&c->user_agent, "user-agent", u->priv_data);

 
         // get the previous cookies & set back to null if string size is zero

         update_options(&c->cookies, "cookies", u->priv_data);

 
         // get the previous headers & set back to null if string size is zero

         update_options(&c->headers, "headers", u->priv_data);

     }
 

     if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
         goto fail;
 
     if (c->n_variants == 0) {
         av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
         ret = AVERROR_EOF;
         goto fail;
     }

     /* If the playlist only contained playlists (Master Playlist),
      * parse each individual playlist. */
     if (c->n_playlists > 1 || c->playlists[0]->n_segments == 0) {
         for (i = 0; i < c->n_playlists; i++) {
             struct playlist *pls = c->playlists[i];
             if ((ret = parse_playlist(c, pls->url, pls, NULL)) < 0)

                 goto fail;
         }
     }
 

     if (c->variants[0]->playlists[0]->n_segments == 0) {

         av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
         ret = AVERROR_EOF;
         goto fail;
     }
 
     /* If this isn't a live stream, calculate the total duration of the
      * stream. */

     if (c->variants[0]->playlists[0]->finished) {

         int64_t duration = 0;

         for (i = 0; i < c->variants[0]->playlists[0]->n_segments; i++)
             duration += c->variants[0]->playlists[0]->segments[i]->duration;

         s->duration = duration;

     }
 

     /* Associate renditions with variants */
     for (i = 0; i < c->n_variants; i++) {
         struct variant *var = c->variants[i];
 
         if (var->audio_group[0])
             add_renditions_to_variant(c, var, AVMEDIA_TYPE_AUDIO, var->audio_group);
         if (var->video_group[0])
             add_renditions_to_variant(c, var, AVMEDIA_TYPE_VIDEO, var->video_group);
         if (var->subtitles_group[0])
             add_renditions_to_variant(c, var, AVMEDIA_TYPE_SUBTITLE, var->subtitles_group);
     }
 

     /* Open the demuxer for each playlist */
     for (i = 0; i < c->n_playlists; i++) {
         struct playlist *pls = c->playlists[i];

         AVInputFormat *in_fmt = NULL;

         if (!(pls->ctx = avformat_alloc_context())) {

             ret = AVERROR(ENOMEM);
             goto fail;
         }
 

         if (pls->n_segments == 0)
             continue;
 

         pls->index  = i;
         pls->needed = 1;
         pls->parent = s;

         pls->cur_seq_no = select_cur_seq_no(c, pls);

         pls->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);

         if (!pls->read_buffer){
             ret = AVERROR(ENOMEM);
             avformat_free_context(pls->ctx);
             pls->ctx = NULL;
             goto fail;
         }

         ffio_init_context(&pls->pb, pls->read_buffer, INITIAL_BUFFER_SIZE, 0, pls,

                           read_data, NULL, NULL);

         pls->pb.seekable = 0;
         ret = av_probe_input_buffer(&pls->pb, &in_fmt, pls->segments[0]->url,

                                     NULL, 0, 0);

         if (ret < 0) {
             /* Free the ctx - it isn't initialized properly at this point,
              * so avformat_close_input shouldn't be called. If
              * avformat_open_input fails below, it frees and zeros the
              * context, so it doesn't need any special treatment like this. */

             av_log(s, AV_LOG_ERROR, "Error when loading first segment '%s'\n", pls->segments[0]->url);
             avformat_free_context(pls->ctx);
             pls->ctx = NULL;

             goto fail;

         }

         pls->ctx->pb       = &pls->pb;
         pls->stream_offset = stream_offset;

         if ((ret = ff_copy_whitelists(pls->ctx, s)) < 0)
             goto fail;

         ret = avformat_open_input(&pls->ctx, pls->segments[0]->url, in_fmt, NULL);

         if (ret < 0)
             goto fail;

         if (pls->id3_deferred_extra && pls->ctx->nb_streams == 1) {
             ff_id3v2_parse_apic(pls->ctx, &pls->id3_deferred_extra);
             avformat_queue_attached_pictures(pls->ctx);
             ff_id3v2_free_extra_meta(&pls->id3_deferred_extra);
             pls->id3_deferred_extra = NULL;
         }
 

         pls->ctx->ctx_flags &= ~AVFMTCTX_NOHEADER;
         ret = avformat_find_stream_info(pls->ctx, NULL);

         if (ret < 0)
             goto fail;

         if (pls->is_id3_timestamped == -1)
             av_log(s, AV_LOG_WARNING, "No expected HTTP requests have been made\n");
 

         /* Create new AVStreams for each stream in this playlist */
         for (j = 0; j < pls->ctx->nb_streams; j++) {

             AVStream *st = avformat_new_stream(s, NULL);

             AVStream *ist = pls->ctx->streams[j];

             if (!st) {
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }

             st->id = i;

             avcodec_copy_context(st->codec, pls->ctx->streams[j]->codec);

 
             if (pls->is_id3_timestamped) /* custom timestamps via id3 */
                 avpriv_set_pts_info(st, 33, 1, MPEG_TIME_BASE);
             else
                 avpriv_set_pts_info(st, ist->pts_wrap_bits, ist->time_base.num, ist->time_base.den);

         }
 

         add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_AUDIO);
         add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_VIDEO);
         add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_SUBTITLE);
 

         stream_offset += pls->ctx->nb_streams;
     }
 
     /* Create a program for each variant */
     for (i = 0; i < c->n_variants; i++) {
         struct variant *v = c->variants[i];
         AVProgram *program;
 
         program = av_new_program(s, i);
         if (!program)
             goto fail;

         av_dict_set_int(&program->metadata, "variant_bitrate", v->bandwidth, 0);

 
         for (j = 0; j < v->n_playlists; j++) {
             struct playlist *pls = v->playlists[j];
             int is_shared = playlist_in_multiple_variants(c, pls);
             int k;
 
             for (k = 0; k < pls->ctx->nb_streams; k++) {
                 struct AVStream *st = s->streams[pls->stream_offset + k];
 
                 ff_program_add_stream_index(s, i, pls->stream_offset + k);
 
                 /* Set variant_bitrate for streams unique to this variant */
                 if (!is_shared && v->bandwidth)

                     av_dict_set_int(&st->metadata, "variant_bitrate", v->bandwidth, 0);

             }

         }
     }
 
     return 0;
 fail:

     free_playlist_list(c);

     free_variant_list(c);

     free_rendition_list(c);

     return ret;
 }
 

 static int recheck_discard_flags(AVFormatContext *s, int first)

 {

     HLSContext *c = s->priv_data;

     int i, changed = 0;

     /* Check if any new streams are needed */

     for (i = 0; i < c->n_playlists; i++)
         c->playlists[i]->cur_needed = 0;

 
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];

         struct playlist *pls = c->playlists[s->streams[i]->id];

         if (st->discard < AVDISCARD_ALL)

             pls->cur_needed = 1;

     }

     for (i = 0; i < c->n_playlists; i++) {
         struct playlist *pls = c->playlists[i];
         if (pls->cur_needed && !pls->needed) {
             pls->needed = 1;

             changed = 1;

             pls->cur_seq_no = select_cur_seq_no(c, pls);

             pls->pb.eof_reached = 0;

             if (c->cur_timestamp != AV_NOPTS_VALUE) {
                 /* catch up */
                 pls->seek_timestamp = c->cur_timestamp;
                 pls->seek_flags = AVSEEK_FLAG_ANY;

                 pls->seek_stream_index = -1;

             }
             av_log(s, AV_LOG_INFO, "Now receiving playlist %d, segment %d\n", i, pls->cur_seq_no);

         } else if (first && !pls->cur_needed && pls->needed) {
             if (pls->input)
                 ffurl_close(pls->input);
             pls->input = NULL;
             pls->needed = 0;

             changed = 1;

             av_log(s, AV_LOG_INFO, "No longer receiving playlist %d\n", i);

         }
     }

     return changed;

 }
 

 static void fill_timing_for_id3_timestamped_stream(struct playlist *pls)
 {
     if (pls->id3_offset >= 0) {
         pls->pkt.dts = pls->id3_mpegts_timestamp +
                                  av_rescale_q(pls->id3_offset,
                                               pls->ctx->streams[pls->pkt.stream_index]->time_base,
                                               MPEG_TIME_BASE_Q);
         if (pls->pkt.duration)
             pls->id3_offset += pls->pkt.duration;
         else
             pls->id3_offset = -1;
     } else {
         /* there have been packets with unknown duration
          * since the last id3 tag, should not normally happen */
         pls->pkt.dts = AV_NOPTS_VALUE;
     }
 
     if (pls->pkt.duration)
         pls->pkt.duration = av_rescale_q(pls->pkt.duration,
                                          pls->ctx->streams[pls->pkt.stream_index]->time_base,
                                          MPEG_TIME_BASE_Q);
 
     pls->pkt.pts = AV_NOPTS_VALUE;
 }
 
 static AVRational get_timebase(struct playlist *pls)
 {
     if (pls->is_id3_timestamped)
         return MPEG_TIME_BASE_Q;
 
     return pls->ctx->streams[pls->pkt.stream_index]->time_base;
 }
 

 static int compare_ts_with_wrapdetect(int64_t ts_a, struct playlist *pls_a,
                                       int64_t ts_b, struct playlist *pls_b)
 {
     int64_t scaled_ts_a = av_rescale_q(ts_a, get_timebase(pls_a), MPEG_TIME_BASE_Q);
     int64_t scaled_ts_b = av_rescale_q(ts_b, get_timebase(pls_b), MPEG_TIME_BASE_Q);
 
     return av_compare_mod(scaled_ts_a, scaled_ts_b, 1LL << 33);
 }
 

 static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)

 {

     HLSContext *c = s->priv_data;

     int ret, i, minplaylist = -1;

     recheck_discard_flags(s, c->first_packet);

     for (i = 0; i < c->n_playlists; i++) {
         struct playlist *pls = c->playlists[i];
         /* Make sure we've got one buffered packet from each open playlist

          * stream */

         if (pls->needed && !pls->pkt.data) {

             while (1) {
                 int64_t ts_diff;

                 AVRational tb;

                 ret = av_read_frame(pls->ctx, &pls->pkt);

                 if (ret < 0) {

                     if (!avio_feof(&pls->pb) && ret != AVERROR_EOF)

                         return ret;

                     reset_packet(&pls->pkt);

                     break;

                 } else {

                     /* stream_index check prevents matching picture attachments etc. */
                     if (pls->is_id3_timestamped && pls->pkt.stream_index == 0) {
                         /* audio elementary streams are id3 timestamped */
                         fill_timing_for_id3_timestamped_stream(pls);
                     }
 

                     if (c->first_timestamp == AV_NOPTS_VALUE &&

                         pls->pkt.dts       != AV_NOPTS_VALUE)
                         c->first_timestamp = av_rescale_q(pls->pkt.dts,

                             get_timebase(pls), AV_TIME_BASE_Q);

                 }
 

                 if (pls->seek_timestamp == AV_NOPTS_VALUE)

                     break;
 

                 if (pls->seek_stream_index < 0 ||
                     pls->seek_stream_index == pls->pkt.stream_index) {

                     if (pls->pkt.dts == AV_NOPTS_VALUE) {
                         pls->seek_timestamp = AV_NOPTS_VALUE;
                         break;
                     }
 
                     tb = get_timebase(pls);
                     ts_diff = av_rescale_rnd(pls->pkt.dts, AV_TIME_BASE,
                                             tb.den, AV_ROUND_DOWN) -
                             pls->seek_timestamp;
                     if (ts_diff >= 0 && (pls->seek_flags  & AVSEEK_FLAG_ANY ||
                                         pls->pkt.flags & AV_PKT_FLAG_KEY)) {
                         pls->seek_timestamp = AV_NOPTS_VALUE;
                         break;
                     }

                 }

                 av_free_packet(&pls->pkt);
                 reset_packet(&pls->pkt);

             }
         }

         /* Check if this stream has the packet with the lowest dts */

         if (pls->pkt.data) {
             struct playlist *minpls = minplaylist < 0 ?
                                      NULL : c->playlists[minplaylist];

             if (minplaylist < 0) {

                 minplaylist = i;

             } else {

                 int64_t dts     =    pls->pkt.dts;
                 int64_t mindts  = minpls->pkt.dts;

                 if (dts == AV_NOPTS_VALUE ||
                     (mindts != AV_NOPTS_VALUE && compare_ts_with_wrapdetect(dts, pls, mindts, minpls) < 0))

                     minplaylist = i;

             }

         }
     }

     /* If we got a packet, return it */

     if (minplaylist >= 0) {

         struct playlist *pls = c->playlists[minplaylist];
         *pkt = pls->pkt;
         pkt->stream_index += pls->stream_offset;

         reset_packet(&c->playlists[minplaylist]->pkt);

 
         if (pkt->dts != AV_NOPTS_VALUE)
             c->cur_timestamp = av_rescale_q(pkt->dts,
                                             pls->ctx->streams[pls->pkt.stream_index]->time_base,
                                             AV_TIME_BASE_Q);
 

         return 0;
     }

     return AVERROR_EOF;

 }
 

 static int hls_close(AVFormatContext *s)

 {

     HLSContext *c = s->priv_data;

     free_playlist_list(c);

     free_variant_list(c);

     free_rendition_list(c);

     return 0;
 }
 

 static int hls_read_seek(AVFormatContext *s, int stream_index,

                                int64_t timestamp, int flags)
 {

     HLSContext *c = s->priv_data;

     struct playlist *seek_pls = NULL;
     int i, seq_no;

     int64_t first_timestamp, seek_timestamp, duration;

     if ((flags & AVSEEK_FLAG_BYTE) ||
         !(c->variants[0]->playlists[0]->finished || c->variants[0]->playlists[0]->type == PLS_TYPE_EVENT))

         return AVERROR(ENOSYS);
 

     first_timestamp = c->first_timestamp == AV_NOPTS_VALUE ?
                       0 : c->first_timestamp;
 

     seek_timestamp = av_rescale_rnd(timestamp, AV_TIME_BASE,

                                     s->streams[stream_index]->time_base.den,
                                     flags & AVSEEK_FLAG_BACKWARD ?
                                     AV_ROUND_DOWN : AV_ROUND_UP);
 

     duration = s->duration == AV_NOPTS_VALUE ?
                0 : s->duration;
 
     if (0 < duration && duration < seek_timestamp - first_timestamp)

         return AVERROR(EIO);

     /* find the playlist with the specified stream */

     for (i = 0; i < c->n_playlists; i++) {
         struct playlist *pls = c->playlists[i];

         if (stream_index >= pls->stream_offset &&
             stream_index - pls->stream_offset < pls->ctx->nb_streams) {
             seek_pls = pls;

             break;
         }

     }

     /* check if the timestamp is valid for the playlist with the
      * specified stream index */
     if (!seek_pls || !find_timestamp_in_playlist(c, seek_pls, seek_timestamp, &seq_no))

         return AVERROR(EIO);
 

     /* set segment now so we do not need to search again below */
     seek_pls->cur_seq_no = seq_no;
     seek_pls->seek_stream_index = stream_index - seek_pls->stream_offset;
 

     for (i = 0; i < c->n_playlists; i++) {

         /* Reset reading */

         struct playlist *pls = c->playlists[i];
         if (pls->input) {
             ffurl_close(pls->input);
             pls->input = NULL;

         }

         av_free_packet(&pls->pkt);
         reset_packet(&pls->pkt);
         pls->pb.eof_reached = 0;

         /* Clear any buffered data */

         pls->pb.buf_end = pls->pb.buf_ptr = pls->pb.buffer;

         /* Reset the pos, to let the mpegts demuxer know we've seeked. */

         pls->pb.pos = 0;

         /* Flush the packet queue of the subdemuxer. */
         ff_read_frame_flush(pls->ctx);

         pls->seek_timestamp = seek_timestamp;
         pls->seek_flags = flags;
 

         if (pls != seek_pls) {
             /* set closest segment seq_no for playlists not handled above */

             find_timestamp_in_playlist(c, pls, seek_timestamp, &pls->cur_seq_no);

             /* seek the playlist to the given position without taking
              * keyframes into account since this playlist does not have the
              * specified stream where we should look for the keyframes */
             pls->seek_stream_index = -1;
             pls->seek_flags |= AVSEEK_FLAG_ANY;
         }

     }

     c->cur_timestamp = seek_timestamp;
 

     return 0;

 }
 

 static int hls_probe(AVProbeData *p)

 {
     /* Require #EXTM3U at the start, and either one of the ones below
      * somewhere for a proper match. */
     if (strncmp(p->buf, "#EXTM3U", 7))
         return 0;
     if (strstr(p->buf, "#EXT-X-STREAM-INF:")     ||
         strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
         strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
         return AVPROBE_SCORE_MAX;
     return 0;
 }
 

 #define OFFSET(x) offsetof(HLSContext, x)
 #define FLAGS AV_OPT_FLAG_DECODING_PARAM
 static const AVOption hls_options[] = {
     {"live_start_index", "segment index to start live streams at (negative values are from the end)",
         OFFSET(live_start_index), FF_OPT_TYPE_INT, {.i64 = -3}, INT_MIN, INT_MAX, FLAGS},
     {NULL}
 };
 
 static const AVClass hls_class = {
     .class_name = "hls,applehttp",
     .item_name  = av_default_item_name,
     .option     = hls_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 AVInputFormat ff_hls_demuxer = {

     .name           = "hls,applehttp",

     .long_name      = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming"),

     .priv_class     = &hls_class,

     .priv_data_size = sizeof(HLSContext),
     .read_probe     = hls_probe,
     .read_header    = hls_read_header,
     .read_packet    = hls_read_packet,
     .read_close     = hls_close,
     .read_seek      = hls_read_seek,

 };